There are two common forms of disposable articles that are designed to absorb menstrual fluids discharged from a female's cervix. The first article is intended to be wholly inserted into the vaginal canal, and positioned near or against the cervical os. These articles are commonly referred to as catemenial tampons, or simply tampons. Some of the disadvantages related to tampons are the following: they can be attributed to excessive vaginal drying, they have been associated with toxic shock syndrome, they can be uncomfortable to insert and remove, especially on light flow days, and they have limited absorbing capacity, due to the regulations set by the U.S. Food and Drug Administration.
The second widely known and used article for collecting menstrual fluids is the sanitary napkin. This product is designed to be worn external to the vagina. Sanitary napkins can also be used to absorb urine, due to the size and positioning against the perineum. The product can be attached to the crotch of undergarments, attached directly to the vulvar region with body adhesives, and also worn partially or totally between the labia minora and majora. Many consumers choose to wear external absorbent articles because of their concern of toxic shock syndrome, they have difficulty inserting and removing tampons, they have difficulty wearing tampons, and they have a need for higher absorbing capacity than that available from tampons. As with tampons however, there are disadvantages that have been voiced by consumers who rely on external absorbing articles for their fluid management needs.
One perceived disadvantage of external sanitary napkins is their association with odors. Menstrual fluid contains a variety of substances including proteins and lipids. Microbial action on proteins has been recognized as a source of malodor. Urine is another fluid that can be absorbed by sanitary protection products, and microbial activity can form ammonia from urea in excreted urine. Consumers complain of not feeling "fresh" during their period, and hence seek out products that claim to control odor issues.
There have been a number of technologies developed for controlling odors associated with bodily fluids; particularly those attributed to perspiration, menstrual fluid degradation products, urine degradation products, and miscellaneous urine odors. Nearly all of the technologies can be placed into three main subcategories. The first is the use of added materials to absorb or adsorb volatile odors in an effort to restrict their release to the environment surrounding the consumer. Materials or compositions that adsorb and/or absorb volatile odors include sodium bicarbonate, sodium salts or ethylenediamine tetraacetic acid (EDTA), activated carbon, zeolites, and mixtures of sodium bicarbonate, EDTA, and activated carbon. These approaches are disclosed in U.S. Pat. No. 4,237,591 and 5,306,487. The second is the use of masking materials, such as perfumes, and the third is the use of substances to inhibit the production of bodily fluid degradation products. U.S. Pat. No. 5,733,272 discloses absorbent articles containing compositions of moisture-activated encapsulated perfumes and odor-controlling agents, including anti-microbial compounds.
The discussion thus far has highlighted technologies that are believed to remedy either malodors directly by inhibiting microbial activity, thereby decreasing the level of urine and menses degradation products, or indirectly by suppressing or overcoming the odors as they exist.